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package org.hisp.dhis.analytics.event.data.programindicator.disag;

import static java.util.stream.Collectors.toMap;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import org.hisp.dhis.analytics.DataQueryParams;
import org.hisp.dhis.category.Category;
import org.hisp.dhis.common.DimensionalItemObject;
import org.hisp.dhis.common.IdentifiableObjectManager;
import org.hisp.dhis.program.ProgramCategoryMapping;
import org.hisp.dhis.program.ProgramIndicator;

/**
 * Finder of analytics recommended categories for disaggregated program indicators.
 *
 * @author Jim Grace
 */
public class PiDisagRecommendedDimensions {
  PiDisagRecommendedDimensions() {
    throw new IllegalStateException("Utility class");
  }

  public static List<Category> getRecommendations(
      DataQueryParams params, IdentifiableObjectManager idObjectManager) {
    List<DimensionalItemObject> pis = params.getProgramIndicators();

    return idObjectManager.getByUid(
        Category.class,
        pis.stream()
            .map(pi -> getCategoryIds((ProgramIndicator) pi))
            .flatMap(Collection::stream)
            .toList());
  }

  private static List<String> getCategoryIds(ProgramIndicator pi) {
    // For the program of the program indicator, get a map from mappings to category Ids.
    Map<String, String> mappingCategoryMap =
        pi.getProgram().getCategoryMappings().stream()
            .collect(toMap(ProgramCategoryMapping::getId, ProgramCategoryMapping::getCategoryId));
    // Return all the category IDs referenced from the program indicator
    return pi.getCategoryMappingIds().stream().map(mappingCategoryMap::get).toList();
  }
}
